Node.js Advanced Patterns

Advanced patterns for dependency injection, database integration, authentication, caching, and API response formatting. Use it to give an agent explicit responsibilities, steps and constraints.

Editorial note: curated source snapshot published by Collider.club under the MIT License. Source attribution is preserved in the front matter.

Source snapshot

Node.js Advanced Patterns

Advanced patterns for dependency injection, database integration, authentication, caching, and API response formatting.

Dependency Injection

DI Container

// di-container.ts
import { Pool } from "pg";
import { UserRepository } from "./repositories/user.repository";
import { UserService } from "./services/user.service";
import { UserController } from "./controllers/user.controller";
import { AuthService } from "./services/auth.service";

class Container {
  private instances = new Map<string, any>();

  register<T>(key: string, factory: () => T): void {
    this.instances.set(key, factory);
  }

  resolve<T>(key: string): T {
    const factory = this.instances.get(key);
    if (!factory) {
      throw new Error(`No factory registered for ${key}`);
    }
    return factory();
  }

  singleton<T>(key: string, factory: () => T): void {
    let instance: T;
    this.instances.set(key, () => {
      if (!instance) {
        instance = factory();
      }
      return instance;
    });
  }
}

export const container = new Container();

// Register dependencies
container.singleton(
  "db",
  () =>
    new Pool({
      host: process.env.DB_HOST,
      port: parseInt(process.env.DB_PORT || "5432"),
      database: process.env.DB_NAME,
      user: process.env.DB_USER,
      password: process.env.DB_PASSWORD,
      max: 20,
      idleTimeoutMillis: 30000,
      connectionTimeoutMillis: 2000,
    }),
);

container.singleton(
  "userRepository",
  () => new UserRepository(container.resolve("db")),
);

container.singleton(
  "userService",
  () => new UserService(container.resolve("userRepository")),
);

container.register(
  "userController",
  () => new UserController(container.resolve("userService")),
);

container.singleton(
  "authService",
  () => new AuthService(container.resolve("userRepository")),
);

Database Patterns

PostgreSQL with Connection Pool

// config/database.ts
import { Pool, PoolConfig } from "pg";

const poolConfig: PoolConfig = {
  host: process.env.DB_HOST,
  port: parseInt(process.env.DB_PORT || "5432"),
  database: process.env.DB_NAME,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  max: 20,
  idleTimeoutMillis: 30000,
  connectionTimeoutMillis: 2000,
};

export const pool = new Pool(poolConfig);

// Test connection
pool.on("connect", () => {
  console.log("Database connected");
});

pool.on("error", (err) => {
  console.error("Unexpected database error", err);
  process.exit(-1);
});

// Graceful shutdown
export const closeDatabase = async () => {
  await pool.end();
  console.log("Database connection closed");
};

MongoDB with Mongoose

// config/mongoose.ts
import mongoose from "mongoose";

const connectDB = async () => {
  try {
    await mongoose.connect(process.env.MONGODB_URI!, {
      maxPoolSize: 10,
      serverSelectionTimeoutMS: 5000,
      socketTimeoutMS: 45000,
    });

    console.log("MongoDB connected");
  } catch (error) {
    console.error("MongoDB connection error:", error);
    process.exit(1);
  }
};

mongoose.connection.on("disconnected", () => {
  console.log("MongoDB disconnected");
});

mongoose.connection.on("error", (err) => {
  console.error("MongoDB error:", err);
});

export { connectDB };

// Model example
import { Schema, model, Document } from "mongoose";

interface IUser extends Document {
  name: string;
  email: string;
  password: string;
  createdAt: Date;
  updatedAt: Date;
}

const userSchema = new Schema<IUser>(
  {
    name: { type: String, required: true },
    email: { type: String, required: true, unique: true },
    password: { type: String, required: true },
  },
  {
    timestamps: true,
  },
);

// Indexes
userSchema.index({ email: 1 });

export const User = model<IUser>("User", userSchema);

Transaction Pattern

// services/order.service.ts
import { Pool } from "pg";

export class OrderService {
  constructor(private db: Pool) {}

  async createOrder(userId: string, items: any[]) {
    const client = await this.db.connect();

    try {
      await client.query("BEGIN");

      // Create order
      const orderResult = await client.query(
        "INSERT INTO orders (user_id, total) VALUES ($1, $2) RETURNING id",
        [userId, calculateTotal(items)],
      );
      const orderId = orderResult.rows[0].id;

      // Create order items
      for (const item of items) {
        await client.query(
          "INSERT INTO order_items (order_id, product_id, quantity, price) VALUES ($1, $2, $3, $4)",
          [orderId, item.productId, item.quantity, item.price],
        );

        // Update inventory
        await client.query(
          "UPDATE products SET stock = stock - $1 WHERE id = $2",
          [item.quantity, item.productId],
        );
      }

      await client.query("COMMIT");
      return orderId;
    } catch (error) {
      await client.query("ROLLBACK");
      throw error;
    } finally {
      client.release();
    }
  }
}

Authentication & Authorization

JWT Authentication

// services/auth.service.ts
import jwt from "jsonwebtoken";
import bcrypt from "bcrypt";
import { UserRepository } from "../repositories/user.repository";
import { UnauthorizedError } from "../utils/errors";

export class AuthService {
  constructor(private userRepository: UserRepository) {}

  async login(email: string, password: string) {
    const user = await this.userRepository.findByEmail(email);

    if (!user) {
      throw new UnauthorizedError("Invalid credentials");
    }

    const isValid = await bcrypt.compare(password, user.password);

    if (!isValid) {
      throw new UnauthorizedError("Invalid credentials");
    }

    const token = this.generateToken({
      userId: user.id,
      email: user.email,
    });

    const refreshToken = this.generateRefreshToken({
      userId: user.id,
    });

    return {
      token,
      refreshToken,
      user: {
        id: user.id,
        name: user.name,
        email: user.email,
      },
    };
  }

  async refreshToken(refreshToken: string) {
    try {
      const payload = jwt.verify(
        refreshToken,
        process.env.REFRESH_TOKEN_SECRET!,
      ) as { userId: string };

      const user = await this.userRepository.findById(payload.userId);

      if (!user) {
        throw new UnauthorizedError("User not found");
      }

      const token = this.generateToken({
        userId: user.id,
        email: user.email,
      });

      return { token };
    } catch (error) {
      throw new UnauthorizedError("Invalid refresh token");
    }
  }

  private generateToken(payload: any): string {
    return jwt.sign(payload, process.env.JWT_SECRET!, {
      expiresIn: "15m",
    });
  }

  private generateRefreshToken(payload: any): string {
    return jwt.sign(payload, process.env.REFRESH_TOKEN_SECRET!, {
      expiresIn: "7d",
    });
  }
}

Caching Strategies

// utils/cache.ts
import Redis from "ioredis";

const redis = new Redis({
  host: process.env.REDIS_HOST,
  port: parseInt(process.env.REDIS_PORT || "6379"),
  retryStrategy: (times) => {
    const delay = Math.min(times * 50, 2000);
    return delay;
  },
});

export class CacheService {
  async get<T>(key: string): Promise<T | null> {
    const data = await redis.get(key);
    return data ? JSON.parse(data) : null;
  }

  async set(key: string, value: any, ttl?: number): Promise<void> {
    const serialized = JSON.stringify(value);
    if (ttl) {
      await redis.setex(key, ttl, serialized);
    } else {
      await redis.set(key, serialized);
    }
  }

  async delete(key: string): Promise<void> {
    await redis.del(key);
  }

  async invalidatePattern(pattern: string): Promise<void> {
    const keys = await redis.keys(pattern);
    if (keys.length > 0) {
      await redis.del(...keys);
    }
  }
}

// Cache decorator
export function Cacheable(ttl: number = 300) {
  return function (
    target: any,
    propertyKey: string,
    descriptor: PropertyDescriptor,
  ) {
    const originalMethod = descriptor.value;

    descriptor.value = async function (...args: any[]) {
      const cache = new CacheService();
      const cacheKey = `${propertyKey}:${JSON.stringify(args)}`;

      const cached = await cache.get(cacheKey);
      if (cached) {
        return cached;
      }

      const result = await originalMethod.apply(this, args);
      await cache.set(cacheKey, result, ttl);

      return result;
    };

    return descriptor;
  };
}

API Response Format

// utils/response.ts
import { Response } from "express";

export class ApiResponse {
  static success<T>(
    res: Response,
    data: T,
    message?: string,
    statusCode = 200,
  ) {
    return res.status(statusCode).json({
      status: "success",
      message,
      data,
    });
  }

  static error(res: Response, message: string, statusCode = 500, errors?: any) {
    return res.status(statusCode).json({
      status: "error",
      message,
      ...(errors && { errors }),
    });
  }

  static paginated<T>(
    res: Response,
    data: T[],
    page: number,
    limit: number,
    total: number,
  ) {
    return res.json({
      status: "success",
      data,
      pagination: {
        page,
        limit,
        total,
        pages: Math.ceil(total / limit),
      },
    });
  }
}

About Collider.club

This card belongs to the curated knowledge base of Collider.club — a closed business club for entrepreneurs, engineers, investors and domain experts building projects for international markets. Members work across DeFi, AI/ML, FinTech, Web3, banking, hardware and venture capital, and the club runs closed sessions on high-margin niches with anonymous speakers.

• Club: https://collider.club
• Collection: Collider.club curated card library (mdrss-card/v2)
• Maintainer: Collider.club editorial team

License

MIT License — Copyright (c) 2026 Collider.club. Full text: LICENSE · https://opensource.org/licenses/MIT